Ice making machines are in widespread use for supplying cube ice in commercial operations. Typically, ice making machines produce a large quantity of clear ice by flowing water a chilled surface. The chilled surface is thermally coupled to evaporator coils that are, in turn, coupled to a refrigeration system. The chilled surface commonly contains a large number of indentations on its surface where water flowing over the surface can collect. As water flows over the indentations, it freezes into cube ice.
To harvest the ice, the evaporator coils are heated by hot, compressed refrigerant flowing through the evaporator coils, by heating elements located proximate the ice, and/or in other manners. Heat can be transferred to the chilled surface until it is warmed to a temperature sufficient to harvest the ice from the surface. Once freed from the surface, the ice cubes fall into an ice storage bin. The ice cubes produced by a typical ice making machine are pre-formed or regular in shape, and in some embodiments have a generally thin profile. In some ice making machines, the cubes are released from the chilled surface as individual cubes, while in other ice machines, the cubes are connected by a thin bridge of ice that is commonly fractured upon the ice falling into the storage bin.
Evaporators are commonly made using copper tubing in thermal contact with the chilled surface. Low-pressure, expanded refrigerant is passed through the copper tubing to chill the evaporator. The copper tubing can be secured (e.g. typically soldered or brazed) to a copper plate that distributes the chilling effect from the copper tubing. Because the copper tubing is cylindrical in shape, and because the copper plate is typically substantially flat, there is line contact between the two parts, which can reduce the efficiency and speed of heat transfer between the two parts.